JOHANNESBURG - A mineral sands operation on the South African coast run by Rio Tinto has been closed since Friday due to violent community protests which saw a security guard killed earlier this week, the company and a union said on Wednesday.

Community unrest is a common feature of South Africa’s social landscape, which is marred by high jobless rates and glaring income disparities, underscoring the social risks for investors in the country’s mining sector.

“Due to the escalation in activity around the blockades on the access roads, staff were sent home on Friday. Our highest priority is the safety of our people,” a Rio spokesperson said. The operation, Richards Bay Minerals, is on South Africa’s Indian Ocean coast.

Mzi Zakwe, the regional secretary for the National Union of Mineworkers (NUM), told Reuters the union’s 900 members were on forced leave because of the violence, which he said was rooted in grievances between the company and contractors.

Unrest has hit the area before, which is also near South Africa’s main coal terminal.

Elsewhere in South Africa, the eastern limb of the platinum belt was hit by more than 400 incidents of social unrest impacting mining operations since between the start of 2016 and April this year according to data compiled by Anglo American Platinum and reviewed by Reuters.